So I need some help. My son has an allergy/lactose intolerant to my breast milk. We tried Similac Alimentum which worked great for him but is super expensive. our doctor told us to try soy formula. I gave him a bottle and an hour later his tummy was upset and he was doing the same thing he did on the breast milk. my question is how long should I try the soy for to see if he ends up being okay on it? Should I try a couple more feedings? Should I cut it off?